Skeletal muscle ventricles: update after 18 months in circulation.

Skeletal muscle ventricles (SMVs) have been constructed from canine latissimus dorsi muscle and connected to the aorta as aortic diastolic counterpulsators. Presently one dog remains alive and well with an SMV that has been functioning continuously in circulation for 18 months, without evidence of thromboembolic complications. SMVs are able to perform cardiac-type work with an output equal to that of the left ventricle at physiologic preloads, when tested with a mock circulation device in our laboratory. SMVs have been used for right-sided cardiac assist. In acute experiments these ventricles have functioned effectively, bypassing the right side of the heart for up to 8 h. Most recently we have tested SMVs using them chronically to pump blood in the right-sided circulation, and at the time of writing they have been shown to function effectively in this configuration for up to 18 days. SMVs may be used in the future as a method of treating patients with left- or right-sided heart failure.